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lab5_answersdoc - Uwsp

By Eric Barnes,2014-03-28 00:30
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Geog391

    Lab 5 answers

    1) How is the Network Analyst service area operation different from a buffer?

    a) The network analysis uses an impedance attribute which is similar to the distance buffer used in

    the buffer operation. The GIS analyst also has many other options from which to choose when

    deciding on how the service area will be measured. The buffer operation essentially limits the

    analyst to simple “distance from “ operations while the network analyst allows the GIS analyst

    the ability to figure distance’s and time’s to and from specific points within the network with or

    without restrictions or limitations.

    b) The Network Analyst service area operation is different than adding a buffer because while a

    buffer would just create a polygon around the designated feature of a certain distance in every

    direction, a service area does the same thing, but using a walkable distance as defined by the

    road network. This essentially allows one to determine the closest location of a specific type of

    service, whether it be churches, dining or schools, to any structural location within the study

    area as long as that service is within the defined (500 meter) walking distance of that structure

    or residence.

    c) The Network Analyst service area operation is different than a buffer in that it uses the road

    segments as a parameter to measure a distance away from the objects. A buffer goes in a

    straight line distance away from the object measured at 500 meters.

    d) Network Analyst is different from a buffer because a buffer is used to identify areas that

    surround certain geographic features and determine whether features fall inside of the buffer or

    not. Network analysis is usually used to determine routes or to show allocation of services. In a

    network analysis you can determine overlapping areas of different services and see where they

    overlap.

    2) Some walkable areas calculated with the intersect overlay do not have any services inside of them. Is this an error? How can there be walkable areas without any services?

    a) No, I don’t believe that the presence of walkable areas without any services is an error. The

    walkable polygons that exist without any service facilities within the polygon are located

    adjacent to a service facility. The polygon and the facility are contiguous.

    b) This is not an error. The walkable areas calculated through the intersect overlay only display the

    places where the service areas polygons, associated with each type of service, intersect. This

    means that while there are services within the service area polygons, it may occur that there are

    in fact no services contained within the area in which those polygons overlap. c) The walk able areas that don’t have any services are not errors. They are formed because this is

    where all three services are overlaid and have connections between each other. As well this is

    where the 500 meters are covered on the line segments.

    d) This isn’t a mistake. Walkable areas don’t necisarily have to have services in them because they

    show the areas within a certain distance from various services and where distance from the

    different services overlap. So if there are services spaced out they can have networks that

    overlap and don’t have to have a service in them.

    3) How many residential parcels in Stevens Point are in the intersection of walkable service areas? a) There are 1,114 residential parcels that fall within the walkable service area. b)

    CodeZoningCount

    R1Surburban5

    R2Single160

    R3Two - Fam606

    R4Multi - Fam56

    R5Multi - Fam 231

    Total858

    Listed above are all of the counts for the different types of zoning applied to all residential

    parcels within the intersect overlay polygons. There were 1,113 total parcels inside the

    intersect overlay polygons, but only 858 of those were zoned as residential. This may not mean

    that there are exactly 858 residences within the overlapping areas, but there are that many

    parcels within the overlapping areas that are zoned as residential.

    c) There are 113 residential parcels in the 45 walk able service area polygons. There are a total of

    1,114 Stevens Point parcels that are in the 45 walk able polygons. A lot of these parcels are

    owned by the city or are considered other than residential.

    d) There are 950 residential parcels that fall into this walkable area. Did this by doing a combine

    with my walkable analysis and sp_parcels.

    4) How well do the results of your walkability zones agree with the results from www.walkscore.com?

    a) For the most part my walkscores for the parcels that fell within the spatial join shape file created

    from the SP_parcels and walkable layers show that many of the parcels from within these

    polygons had a score ranging from the mid 60’s to the mid 70’s. The only area that I could see

    where being on either side of a major road had an impact on walkscore was for the area on the

    east side of point where the parcels on the north side of Hwy 10E had a lower score than those

    parcels on the south side of Hwy 10.

    b) Above is a table listing residential addresses that both fell within the Intersect Overlay of service

    areas and are listed as being on a major road in Stevens Point. As one can see, the walkscores

    do not vary that much from address to address. However, Clark St. is exceptionally high which is

    expected because it fell within the intersection of a church, educational and dining service area.

    On the other end of the spectrum, the Patch St. address is unusually low for being represented

    in the intersect overlay. I deliver pizzas for a living and pretty much know the exact locations of

    each of these addresses and I can say with confidence that the Patch St. address is not in a good

    walkable location because Patch St. borders the rail yard which limits route options, and there

    are very few services in that area in general.

    c) The Walk Scores do change due to divisions of major roads. One side of the road you can be

    very walk able while on the other you can be somewhat walk able. Also with less major roads

    you soon become car dependant as in the Patch Street residents.

    d) The walkscore results say that 64% of Stevens Point residents have a higher rate. These numbers

    are a little different because 950 of 8,386 parcels are walkable which is a much lower

percentage than 64%. I don’t really see any trend that would make me say there is a large

difference between walkable parcels on different sides of major roads.

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